There are 30 teams in MLB and each team carries 11 or 12 pitchers. That would make between 330-360 pitchers on active rosters in MLB.
Alot.
There are very few sidearm submarine pitchers in the MLB but to name a few there is Mike Myers, Cla Meredith, Chad Bradford, and Mike Koplove.
There are different amount of pitchers in a 40-man roster, whether you have 25 pitchers (in both the starting rotation and the bullpen) or just have 10, in any game, you can use all of your pitchers....